Oregon mountain goat herds occupy rugged, high-elevation rocky terrain, offering hunters a rare once-in-a-lifetime tag opportunity.

Domestic sheep threaten wild bighorn sheep in Oregon by transmitting fatal pneumonia pathogens that evade their isolated immune systems.

Bighorn sheep pneumonia causes severe lung infections in Oregon herds after contact with domestic sheep and goats carrying bacteria.

Bighorn ram horn growth rings and seasonal keratin layers form annuli, providing a reliable method for field judging animal age.

Rocky Mountain bighorn sheep populations in the Wallowa Mountains face complex draw systems, remote habitats, and historical conservation challenges.

Oregon bighorn sheep history and conservation efforts explain where these animals thrive across the high desert and canyon lands.

California bighorn sheep populations in Oregon, their historical decline, and current distribution in eastern canyonlands.

Pronghorn evolution for open plains running instead of leaping explains why these desert animals refuse to jump barbed wire fences.

Pronghorn horn growth and annual shedding involve a permanent bony core and a deciduous keratin sheath dropped every late fall.

Pronghorn speed involves unique physiological adaptations, large hearts, and high endurance allowing sustained paces over several miles.